The invention relates to buckles of a kind suitable for use in a vehicle seat belt system.
Such buckles conventionally comprise a tongue part and a socket part, the tongue part having a tongue with a latch formation, and the socket part having a socket within which the tongue can be releasably latched by a latch mehcanism having a latch member engageable with the lach formation.
Buckles of this kind require the tongue, on insertion into the socket, to engage the latch member to move this out of the path of the tongue to a position from which the latch member returns under spring pressure to latch the tongue in place; the tongue consequently experiences considerable resistance to insertion, and undesirable lateral loading. In some instances therefore the latch members engage the tongue so as to oppose withdrawal with only limited strength. The latch members can in some instances be displayed to release the tongue by inertial forces experienced when the buckle undergoes a sharp deceleration, as during an accident.
It is accordingly an object of the invention to provide a tongue and socket buckle in which the socket latch member is retained in a non-latching position when the tongue is absent from the socket.
It is a further object of the invention to provide a tongue and socket buckle in which the socket latch member is held in the non-latching position in the absence of the tongue from the socket by a catch means releasable by an ejector mechanism spring biassed to eject the tongue from the socket.
It is additionally an object of the invention to provide a tongue and socket buckle with a manually operable release button which is held in the release position after operation and until the tongue re-enters the socket.
It is also an object of the invention to provide a tongue and socket buckle in which insertion of the tongue into the socket is resisted only by an ejector spring for facilitating removal of the tongue on release of the buckle.
It is a further object of the invention to provide a tongue and socket buckle in which the power needed to move the latch member to the locking position on insertion of the tongue is obtained from the previous release of the tongue from the socket.
It is another object of the invention to provide a buckle in which the latch member moves to the latching position transversely of the direction of movement of the tongue to span the socket in which the tongue is received and is supported externally of the socket against withdrawal forces acting on the tongue by means spaced from the socket.